Dehumidification is widely used, for example, for building air-conditioning systems, for controlling humidity, for dehydration of natural gas, and for moisture regulation in protective apparel. Several dehumidification technologies for controlling temperature and humidity in buildings have been reported in the literature including electro-osmotic dehumidification, solid adsorbents, and liquid desiccants. However, these technologies are capitally intensive, and provide no improvement in energy consumption to promote their adoption. Semi-permeable membranes constructed of various polymer materials have also been used to remove water vapor from humid air streams. Water vapor permeability and H2O/N2 selectivity properties of these membranes depend on the materials used in these membranes. For example, separation membranes made from polyether block amides (e.g., PEBAX®-1074) or sulfonated poly(ether ether ketone) (SPEEK) perform reasonably well in humid environments. However, polymer separation membranes are still energy intensive in operation.
More recently, graphene oxide (GO) membranes have attracted attention because small-scale membranes prepared via vacuum filtration have shown promise. However, a variety of problems still exist. Typically set-up options for such arrangements are limited and resulting membranes are generally small. More recently, larger GO membranes have been reported in the literature prepared from dilute GO dispersions from graphite powders, which are cast onto a PTFE plate to produce the GO membranes. However, a remaining problem for conventional GO membranes is their small GO flake diameter (<5 micrometers) that cause membranes made from these flakes to be structurally instable and to fracture easily. Thus, conventional GO membranes must be supported in operation. Accordingly, new methods are needed for making GO membranes with sizes that are easily scaled, are strong and pliable, have GO flakes that are structural stable, and further provide a high water selectivity and a superior water vapor permeability compared, e.g., to N2 gas, for dehumidification applications. The present invention addresses these needs.